Don't guess frame-start on recent traces
Don't guess frame-start on recent traces

If Choreographer#doFrame is present we don't
need to try and guess the start of the frame,
which is actually incorrect in the case of
some forms of deliverInputEvent

Review URL: https://codereview.chromium.org/1305873003

benschmaus/catapult,catapult-project/catapult-csm,catapult-project/catapult-csm,0x90sled/catapult,SummerLW/Perf-Insight-Report,catapult-project/catapult-csm,sahiljain/catapult,scottmcmaster/catapult,benschmaus/catapult,catapult-project/catapult,benschmaus/catapult,sahiljain/catapult,catapult-project/catapult,0x90sled/catapult,0x90sled/catapult,catapult-project/catapult-csm,sahiljain/catapult,SummerLW/Perf-Insight-Report,benschmaus/catapult,catapult-project/catapult-csm,sahiljain/catapult,sahiljain/catapult,catapult-project/catapult,benschmaus/catapult,scottmcmaster/catapult,catapult-project/catapult,SummerLW/Perf-Insight-Report,SummerLW/Perf-Insight-Report,catapult-project/catapult,benschmaus/catapult,catapult-project/catapult-csm,catapult-project/catapult,SummerLW/Perf-Insight-Report,SummerLW/Perf-Insight-Report,catapult-project/catapult,scottmcmaster/catapult,catapult-project/catapult-csm,sahiljain/catapult,benschmaus/catapult